Good Job !
Two fixes I know of for that problem.
I had an '82 Subaru Brat that had a really big bolt circle diameter - I think it was 4 on 140mm.
I had a guy in California make me wheel adapters to go to a Chevy 5 bolt 4 & 3/4" bolt circle diameter (which happens to be the same B.C. diam I want for the Capri).
Four of the 5 studs were normal old wheel adapter studs. The fifth one, however, was cool as can be. It was an offset stud. (It sort of looked like this, only much more of an offset) :
http://retrospec-guitar.com/store/images/offset.jpg What you did was hand thread this offset stud onto a Subaru stud. Then you had to kind of center that offset stud and put the wheel adapter over it, onto the hub.
Tighten the three nuts down onto the wheel adapter which held the adapter to the Subaru hub then put the Chevy wheel on the adapter, tighten the wheel down and you're good to go. I did about 45,000 miles on those adapters and yes, I also did a lot of 4X4 off roading. Every couple of months I checked my lug nut's torque with a torque wrench and a couple of times a year I'd pull the wheels off and recheck the torque on the adapters. From what I remember, I NEVER had any problems with anything.
Nobody wants to do an adapter like that now so the only viable option is to go to a 2 piece adapter. Piece one of the adapter bolts to the Capri hub. Piece two of the adapter is machined for the rims you want and is bolted to piece one of the adapter with counter sunk screws. More work, as far as I'm concerned but if it's my only option...
Either way, it CAN be done and it blows my mind that in this economy, machine shops that are certainly capable of doing this won't do it ! A lot of these adapter prices START at $95 PER wheel...I'm sure they'd charge more for a true custom adapter with an offset stud.
Oh, and for what it's worth, my Kelmark has adapters on it now. '69 VW Beetle four bolt hubs to that same Chevy bolt pattern I'm looking for now. 31 years they've been on the car - again, no problems.
Thanks for the photoshopped image. I wouldn't be able to figure out how to photoshop an image if I had a week to practice.
Dave